1. Field of the Invention
This invention relates to microelectromechanical systems devices. In particular it relates to thin film structures in microelectromechanical systems devices and to electromechanical and optical responses of such thin film structures.
2. Description of the Related Art
Today a wide variety of microelectromechanical systems (MEMS) devices may be fabricated using microfabrication techniques. Examples of these MEMS devices include motors, pumps, valves, switches, sensors, pixels, etc.
Often these MEMS devices harness principles and phenomena from different domains such as the optical, electrical and mechanical domains. Such principles and phenomena, while seemingly difficult to harness in the macroscopic world, can become extremely useful in the microscopic world of MEMS devices, where such phenomena become magnified. For example, electrostatic forces which are generally considered to be too weak in the macroscopic world to be harnessed, are strong enough in the microscopic world of MEMS devices to activate these devices, often at high speeds and with low power consumption.
Materials used in MEMS devices are generally selected based on their inherent properties in the optical, electrical, and mechanical domains and the characteristic response to input, such as for example, a driving or actuation voltage.
One problem affecting the fabrication of MEMS devices is that in some cases, a material having a highly desirable response to input, for example an optical response to incident light, may also have an undesirable response to input, for example, an electromechanical response to an actuation or driving voltage. To overcome, or at least reduce, the undesirable response, new materials have to be found or developed often at great expense.
Another problem with the fabrication of MEMS devices is that sometimes, a material selected for its characteristic response may become damaged due to exposure to chemical agents used during a particular microfabrication process. This causes the material to demonstrate less of the characteristic response to the input.